Fuel burning air heater



INVENTOR. HY 6. BECK T'NYS J7 4l l A 68'@ Fig 5856 2 sHEETs-sHEE H. G. BECK FUEL BURNING AIR HEATER March 17, 1953 Flled Feb 10, 1949 March 17, 1953 H, Q BECK FUEL BURNING AIR HEATER 2 SHEETS--SHEET 2 Filed Feb. 10, 1949 ,28 Y INVENTOR.

32 Hamer Q. aux

Patented Mar. 17, 1953 UNITED STATES OFFICE FUEL BURNING AIR HEATER Harry G. Beck, Birmingham, Ala., assigner of one-half to Fred K. Brown, Birmingham, Ala.

Claims.

My present invention relates to an air heater, and has for an object the provision of a heater which shall have improved heat transfer characteristics so that the maximum amount of heat generated by the burning of fuel is transferred to the air to be heated.

Another object is to provide an air heater embodying a combustion chamber and an air heating chamber, together with sets of lues so constructed and arranged that air to be heated passes through a set of the same disposed in the combustion chamber, and the products of combustion pass through the other set thereof disposed in the air heating chamber, whereby the maximum amount of heat is transferred from the products of combustion to the air to be heated.

My invention further contemplates a heater in which the combustion chamber is disposed in the air heating chamber, the major portion of the air heating chamber lying behind the combustion chamber, the rear wall of the former extending substantially across the latter, said wall also forming respectively the rear iiue sheet ior the set of flues through which passes the air to be heated, and the front flue sheet for the flues through which pass the products of combustion, thus not only adding to the thermal eiciency of the heater but also resulting in a compact, economical construction.

A further object is to provide a heater embodying the above enumerated features and in which the products of combustion, after passing through the i'lues therefor are caused to flow downwardly behind the rear wall of the air heating chamber relatively narrow passages disposed at each corner of the rear wall of the combustion chamber,

and thence to a draft stack, whereby the products of combustion are caused to move slowly downward in contact with a large area of the rear wall of the air heating chamber while at the higher temperature, and are then caused to move upwardly at a high velocity and in contact with a small area of the rear wall after a large part of the heat is removed therefrom, thus increasing substantially the thermal efficiency of the heater.

It is another object of my invention to provide an air heater in which the front lower portion of the combustion chamber is open, permitting heat generated by a heat unit placed therein to radiate directly into the room to be heated, while at the same time the products of combustion from the heat unit are all carried from the room in a closed circuit.

Apparatus embodying the features of my invention is illustrated in the accompanying drawings forming a part of this application in which:

Fig. 1 is a front elevational view, partly broken away in section;

Fig. 2 is a vertical sectional view taken generally along line II-Il of Fig. 1;

Fig. 3 is a somewhat diagrammatic perspective view with certain portions of the outer jacket broken away to disclose some of the interior parts;

Fig. a is an enlarged detail sectional view taken generally along line IV--IV of Fig. 2;

Fig. 5 is an enlarged detail sectional view taken generally along line V-V of Fig. 2;

Fig. 6 is a sectional view taken along line VI- VI of Fig. 1;

Fig. 7 is a sectional view taken along line VII- VII of Fig. 1, some of the iiues being omitted;

Fig. 8 is a fragmental elevational view, partly broken away and taken along line VIII- VIII of Fig. 7;

Fig. 9 is a perspective view looking at the rear of the front wall of the outer jacket of the heater; and

Figs. 10 and 11 are detail perspective and plan views, respectively, of the cdd shaped fill-in plates used at the upper and lower corners of the opening in the front wall of the outer jacket.

Referring now to the drawings for a better understanding of my invention, my improved heater comprises a jacket having a front wall It, a rear wall il, and side walls l2, and a top wall i3. in the manner well understood, the walls are joined together at the meeting points by welding or otherwise. The jacket is supported on a base is comprising a horizontal plate lli, and vertical rear and end walls il and i8. Likewise, the remainder of the structure of the heater is supported principally from the plate I6, as will appear later.

The front wall it of the jacket is formed of a plate havingan opening i9 at its top and a centrally disposed opening 2l adjacent its bottom. The upper edge of the lower opening carries an upwardly and inwardly curved lip 22, substantially coextensive in length with the width of the opening 2i. The lower edge of the opening 2i carries an inwardly turned horizontal flange 23, while the sides of the openings carry inwardly curved lips 2d. The vertical rear edges of the lips E@ are welded along the line 2E to the side plates of a combustion chamber as will later appear. The resulting upper and lower open corners 21 and 2S between the lips 22-24 and 23--24 are closed by odd shaped fill-in plates 29 and 3@ for u filling respectively the openings 2l and 28, thereby to effectively seal around the opening 2| for a purpose later to appear. A plurality of louvers 3l are disposed across the upper opening i9 through which air to be heated passes, and which serve to ornament the front of the heater. As thus shown in Fig. 9, the lower part of the plate i is cut out as indicated at 3E, and the space therebetween may likewise be filled with louvers if desired as shown in Fig. 1.

Disposed with its lower edge abutting the up turned edge of the lip 22 is a plate 34. Secured:

to the plate i6 as by welding along its-lowerl edge,

is a vertical plate 365, which as shown in Fig. 2 is spaced rearwardly of the plate drbehind ther4 lower opening 2l in the plate ill; Weldedto the plate 36, and inclined upwardly andrearwardly therefrom is another plate 3l, bent to provide a horizontal portion and thence bent to provide. a vertical portion 3S. The plate 3.1i. and the portion 39 ofplate- 3l are joined acrosstheir tops bymeans of aplateli. along their rear edges to conform tothe configuration of the rear plate El are securedas by weld-- ingtmtheendsof'plates'B; 35, 3l, and 4l, and are welded along their bottomY edges to the inturned lip 23. The structure just described defines a combustion chamberv C having a rela'- tivel-y shallow lower portion as consideredfrorn front to rear of the heater, and a relatively deeper portion at its top.

Resting onthe plate it, justforwardly of the plate 35 to lie within the bottom'of the combustion chamber C andv behind the opening 2l, is a heat4 unit' indicated generally bythe numeral 44. While the heat unit employed may burn-either solid, liquid or gaseous fuels, I have, for the purpose ofw illustration, shown the saine as comprise ing a gas heater-having the usual refractory backing blocks dil, the burner element i-l, the gas supply line 48, and a control valve 49. Air for combustion may if desiredlbe supplied throughy an elongatedcpening 5d in the flange 23;v

Itis to be noted that the plate 343 is placed rearwardly of the plate le an arnountdepending upon the radius of the lip 22, thereby to define a space between these plates indicated bythe numeral 5 t. Within the deep upper portion of thev combus tion chamber C are a plurality of nues or vair pipes 52; at either end in openings in the plate Sliand'in theverticaliportion beV or" the plate 3l, thus to communicate at their forward ends with the space 5l and provide air passages throughrthe chamber C.

Adjacent the'rear of the plate l@ and secured as by welding to the upper surface-thereof along its loweredge is a vertically extending plate 53. rl'heY plate 53 is'bent to provide a forwardly in clined portion 5d, and thence is bent horizontally and-forwardly to provide a portion 5&3 passing over the upper plate il andin spacedrelation thereto. The plate overhangs' thev plate 34 andis'welded to therfront plate l. rlhe plate 5,3;.andits portions 5d t are spaced from the rearwallsi i and the top wall i301 the outer jacket, thereby to provide communicating spaces andEdrespectively- The plate 53, andits por-` tionsftand extend outwardly to join the end walls l2 of the jacket as indi-cated more particw larlyin-Figs. 6 and '7. Plate 53, and its portions iii-land` together with the end walls I2 of the, outer. jaclzet thus define a space B, closed at its bottom by the plate it, and which I term an air heating chamber. The Vdues 52` thus communi- End plates d2 and d3, out` lThe nues extend rearwardly and are fixed Ving through, the ilues cate with the space lil and with the'charnber B, the plates 3d and vertical portion 3S of plate 3l forming the ue sheets at each end of the nues.

Secured at either end in suitable openings in the rearwardly inclined portion of the plate 3l and the forwardly inclined portion di. of the plate 53 are e, plurality oi' curved flues 5S. The curvature of these nues is such that their rear ends are -higherjthan the forwardLends; The nues .l5 thus communicate-with the-combustion chamber C at a point between its top and bottom, and with the spacel between the rear jacket wall i l and theplate 53.

Referring particularly to Figs. 3, i; and 5, se-

cured to the rear off the plate 53 and extending vertically alongA theinclined portion thereof are spaced bafeplates t! and t2. The bailies Si and E? are spaced relatively far apart with respecttofeach other, and close to the end walls l2 of the jacket to provide a centrally disposed wide spaeeand a pair of relatively narrow vertically extendingspaees @il and Thefbaillestliand are crcssconnected by means of. a baille t5, disposed above the uppermost ones of the lflues 5S; The baffle plates Gl, t2, andI @il thus inclose the rear ends of all of the tubes 5d. excepta minor number thereof which emerge through the` plate 5E; into the spaces G3 and til; The purpose of these tubes in the functioning or" the heater. will be described later.

The base plate it-is provided with an opening el, and connected to this opening isa condut. The conduit. may lead beneath theliloor. 590i a rooininwhichtheheater is located, theconduit may` have .therein an,induction fanii, drivenby` l is provided with an plained, it will beapparent that rheat generated bythe heat unit l1/l rises upwardly into the upper part of the combustion chanlberv C, and in a. whirling niovenientisdrawn through the -dues 59,

fromwhence it passes into the space 5l between-v the plates Stand l i'below-the cross baiile 5t. In

response to the draft from the stach as applied tothe uel, the gases of combustion are caused to movefdownwardly in the space 5l -between the bellies Si and 52and thence to flow. under the lower edges'M thereof, upwardly into thespaces t3, amd64, intothefspace 53' between the plates and i3, and thence to the stack. With the fan 'il in operation, air to be heated is drawn through the louvers 3 l, into the space l, through` the, uesii and into the air heating chamber B, andthence into the conduit 68. Simultaneously, some air in the space 5l is free to pass over'the topof the plate il of theV combustion chamber, and some aroundthe sides thereof and directly into the chamberV E without going through the nues lt will, be apparent that the air is heated in the combustion chamber C while pass- 52, and is further heated after entering chamber B because of the fact that the 'not gases or" combustion are passing through the nues Further, heat is absorbed the air to be heated while the products of con f bustionare moving downwardly in the space 5l,

space lisis connected by a` at which time the gases are still at a relatively high temperature. Once the gases reach the lower edges I4 of the baffles 6l and 62, and enter the relatively narrow spaces 63 and 5A their velocity is increased, and they move upwardli7 and out of the heater at a relatively rapid rate and after most of the heat has been removed therefrom. It is to be noted that spacing the top plate 4I of the combustion chamber C from the plate 5E in eect insulates the hottest part of the system from the coldest part; that is, since some of the air to be heated fiows between the plates M and 56, this relatively cold air absorbs some of the heat from the gases about to go to the stack. Being relatively cool this air readily takes up heat from the plate 56, thus recovering heat which otherwise would be lost. This arrangement materially increases the thermal efficiency of the unit as a whole. In actual practice I have found my improved heater to be considerably more efcient than those types of heaters in which the air passes only through a set of flues.

The purpose of having a relatively few of the iiues 59 exit into the spaces 53 and 6d is to provide a limited amount of draft when first starting the heater, so that any unburned gas has a ready and direct exit to the stack. Since the rear ends of the nues 59 are higher than the forward ends thereof, a natural draft through the flues is provided.

It will also be noted that the heat unit itself is disposed immediately behind the opening 2| in the front plate The same is therefore readily available for servicing, and also thel refractory members G6 radiate heat directly into the room to be heated. It will be obvious however that if my improved heater is to be used as central system, the opening 2| may be completely closed, thereby to cause all of the heat to rise to the to-p of the combustion chamber C, there to be used in heating the air taken in through the louvers 3|. Further, it will be apparent to those skilled in the art that instead of the louvers 3| a cold air return conduit could be connected to the opening i9 of the front plate IB, thereby making the unit suitable for use in a closed system in the manner well understood. Likewise, by omitting the fan 'H or reversing the same, cold air may be drawn in through the opening 6l from whence it flows reversely through the flues 52 and out of the opening in plate I0.

From the foregoing it will be apparent that I have devised an improved heater which is simple of construction and manufacture, and which is eicient and compact. Likewise, by completely sealing around the opening 2i by means of the lips 22 and 24 and the fill-in plates 29 and Sli, there is no chance for the products of combustion to become mixed with the air to be heated.

While I have shown my invention in but one form, it will be obvious to those skilled in the art that it is not so limited, but is susceptible of various changes and modifications without departing from the spirit thereof, and I desire, therefore, that only such limitations shall be placed thereupon as are specifically set forth in the appended claims,

What I claim is:

1. In an air heater a combustion chamber defined by front, rear, top and end plates, there being a centrally disposed opening adjacent the lower end of said front plate, means forming an air inlet passageway adjacent the top of said front plate, a heat unit in the combustion chamber adjacent the opening in said front plate, a

6 plurality of air pipes communicating with said inlet passageway and passing through the front and rear plates adjacent the top of the combustion chamber, rear, top and end walls forming an air heating chamber surrounding the rear, top and end plates of the combustion chamber, a plurality of rows of superposed vertically spaced ues disposed in the air heating chamber connected directly at one end with the combustion chamber at points below the rear ends of said air pipes and opening rearwardly of the rear wall of said air heating chamber, walls disposed rearwardly of the rear Wall of the air heating chamber and operatively associated therewith to define a closed space to which said ues communicate, means to Vent said space, and means to pass air to be heated through the air pipes and into and out the bottom of said heating chamber.

2. In an air heater, an outer jacket comprising front, rear, top, bottom and end walls, front, rear, top and end plates, spaced inwardly of the respectively corresponding walls of said jacket and defining a combustion chamber, there being a centrally disposed opening adjacent the lower end of the front wall of said jacket and an aligned centrally disposed opening adjacent the lower end of the front plate, there being an inlet passageway in the upper portion of the front wall of said jacket in communication with the space between the front wall of said jacket and the front plate of the combustion chamber, a plurality of air pipes communicating with said inlet passageway and passing through said front and rear plates adjacent the top of the combus tion chamber, a partition wall having a portion spaced forwardly of the rear wall of said jacket and another portion spaced beneath the top wall thereof defining a continuous space therebetween, said partition wall and the rear plate of said combustion chamber defining between them an air heating chamber, a plurality of flues disposed in the air heating chamber connected directly at one end with the combustion chamber at points below the rear ends of said air pipes, the other ends of said flues opening rearwardly of said partition wall and communicating with said continuous space, means to vent said continuous space, and means to pass air to be heated through the air pipes and into the heating chamber and out the bottom thereof.

3. In an air heater, an outer jacket having front, rear, top, bottom and end walls, a plate disposed forwardly of the rear wall and having a top portion extending forwardly in spaced relation beneath the top wall of the jacket, said plate being joined along its side edges to the end walls of the jacket thereby defining a closed space extending upwardly along the rear and under the top of the jacket, a draft connection to said space at the top of the jacket, a combustion chamber within said jacket formed of front, rear and end walls joined by a top wall, the top and rear walls of said combustion chamber being spaced from said plate to define therebetween an air heating chamber, the end walls and the upper portion of the front wall of the combustion chamber being spaced from the end walls and the upper portion of the front wall respectively of said jacket, a plurality of air pipes passing through the front and rear walls of said combustion chamber adjacent the top thereof, a heat unit in the combustion chamber, a plurality of flues connected directly at one end with the combustion chamber at points below the rear ends of said airV pipes andA openingv rearwardly of.y said. plate in direct` eommunicationv with said.V

closed. space between the plate andthe outer jacket, there being an inlet passageway in the upper portion of the front wall of said jacket in communication with said air pipes and-with the space between the upper portion of the front wall of said jacket and the upper portion of thefront Wall of the combustion chamber, and means to pass air to be heated through the air ,pipes and into and out the bottom of said air heating chamber.

4. Apparatus as defined in` claim 3` in which said space defined between the plate and the outer jacket is divided by bales into a relatively wide space flanked on either side by relatively narrow spaces, there being a cross bafe con nesting the upper ends of said vertical baiies, andin which the majority of the ues communi cate with the .space between thevertical bafes and beneath the crossbaie, and a minornum-` bei' thereof communicate with said narrow spaces.

5. Apparatus as defined in claim 3 inv Which thev endsk of said 1 ilues connected to the rear. Walle.

ofthe'combustion chamberare at a lowerv level than theends thereof connected to the rear plate.

HARRY G. BECK.

REFERENCES CITED The following references are of record in the file of this patent:

10 UNITED STATES PATENTS Number Name Date 1,547,316 Gehnrich July 28, 1925 1,666,679 Bridge Apr. 17, 1928 1,689,067 Benner Oct, 23, 1928 15 1,730,298 Rynieker Oct. 1, 1929 2,234,628 Dunham Mar. 11, 1941 2,299,901 Johnston Oct. 27, 1942 2,390,483 Wingert Dec. 4, 1945 20 FOREIGN PATENTS Number Country Date 257,202 Great Britain Aug. 26, 1926 255,342 `Switzerland. Jan. 17, 1949 

